PRELIMINARY MOLDING APPARATUS, AND METHOD OF MANUFACTURING AIR SPRING

PROBLEM TO BE SOLVED: To provide a preliminary molding apparatus which easily performs preliminary molding of a cylindrical unvulcanized rubber molding to enhance product accuracy.SOLUTION: A molding die 5 is constituted of an upper molding die 6 and an under molding die 7. The cylindrical unvulcanized rubber molding 3 is arranged between the molding die 5 and a bladder 9. The molding die 5 is composed by radially arranging a plurality of plates 11, 18, and the cylindrical unvulcanized rubber molding 3 is enabled to be externally viewed. A cylinder 8 for lifting the upper molding die 6 is prepared. The bladder 9 and an air supply/discharge section 10 which supplies/discharges air to/from the bladder 9 are prepared. The upper molding die 6 and the under molding die 7 are clamped while supplying/discharging air to/from the bladder 9. When performing the preliminary molding, it is checked by viewing that there is no problem in the cylindrical unvulcanized rubber molding 3.